Automatic grinding machine for mower sickles



Sept. 27, 1949; P, RA|NBOLT ET AL 2,482,934

AUTOMATIC GRINDING MACHINE FOR MOWER SICKLES Filed March 4, 1948 4 sheets-Samet 1 IN VEN TOR.

Cleo ,E 5471557' Pau/ Ramn! A'ITCI RN EYS Sept. 27, 1949.

AUTOMATIC GRINDING MACHINE FOR MOWER SICKLES Filed March 4, 1948 yLr] P. RAINBOLT Er AL 2,482,934

4 Sheets-Sheet 2 INVENTOR.

a' @gi/Mw@ ATTE RN EYS Sept. 27, 1949.- P. RAINBOLT Er AL 2,482,934

' AUTOMATIC GRINDING vMACHINE? FOR MOWER SICKLES Filed March 4, 1948 4' Sheets-Sheet 3 I NVEN TOR.

Sept. 27, 1949. P, RAlNBQLT E -r AL 2,482,934

AUTOMATIC GRINDING MACHINE FOR MOWER SICKLES Filed March 4, 1948 4 sheets-sheet 4 jmnv.

ATI'D R N EYB Patented Sept. 27? 1949 UNITEDSTATES PATENT ori-"ICE AUTOMATIC GRINDING MACHINE FOR MOWER SICKLES Paul Rainbolt and Cleo E. Barber, Albany, Mo. Application March 4, 1948, Serial No. 12,936'Y Claims. (Cl. 51-36) This invention relates to automatic grinding machines of the type used for sharpening tools and the like, andinparticular a rotating V-shaped grinding wheelactuate'drwith a reciprocating and step by step movement wherein the wheel approachesand grinds the ,cutting edges of blades or sections of a sickle or cutter bar of a mower or the like.

The purpose of this invention is to provide means for automatically kgrinding the `blades of a sickle or cutter bar without removing the blades from the bar. Y Y v.

The cutter bar or sickle element of mowers, binders, and the like travels comparatively close to the ground where it strikes stones, small stumps and the like, so that it is subjected to considerable abuse, and therefore the blades or sections thereof require sharpening at comparatively short periods of time. The blades are rivetedto the bar and in removing the blades for sharpening it is necessary to cut the rivets with a chisell driven by aV hammer blow, and the blow of the hammer often breaks the blades. With this thought in mind thisY invention contemplates Va V-s'haped grinding wheel adapted to enter 4the opening -between two blades of a sicklebar and suitable instrumentalities for actuating Athe grindingwheel and moving the wheel along a cutter or sickle bar wherein the wheel enters the opening between each pair of blades and grinds the cutting edges thereof.

The object of this invention is, therefore, to provide a grinding-wheel and means-for operating the same whereby the grinding wheel will travel along a sickle bar of va mower and grind the cutting edges of the blades Yof the bar.

Another object of the invention -is to provide an automatic grinder for blades of sickle bars of mowers which will travel continuously throughout the length .of'thebar without manual control.

Another object of the invention is to provide Van automatic grinder for blades of sickle bars which operates with a reciprocating motion and in whichY the stroke thereof may readily be adjusted.

A further object of the inventionis to provide a machine for automatically grinding the blades of a sickle bar which is of a comparatively simple and economical construction.

With these and other objects andadvantages in view the invention consists of the new and novel combination, construction, and arrangement of parts, as hereinafter more fully described, set

forth in the claims appended hereto,Y and disclosed in the accompanying drawingsforming part hereof,wherein:

y Figure 1 is a View showing an end elevation of the machine; taken on line Iv-I of Figures 2 and3-- Figure 2 is a view showing a rear elevation of the grinding machine takenron line 2-2 of Figure 1, with parts broken away.`

`Figure 3 isa View showing 'a'front elevation of the machine taken Online 3-3 .of Figure 1 with parts broken away.

Figure 4 is a detail illustrating the `grinding wheel mounting and operating instrumentalities with parts omitted and parts broken away.

Figure 5 is a detail showing a section through the grinding wheel taken on line 5-5 of Figure1.

Figure 6 is a detail taken on line 6-6 of Figure 1 showing the ratchet'and dog for advancing the grinding wheel carriage from .one pair of blades to another.

Referring now to'the drawings wherein like reference characters denote' corresponding parts the automatic sickleY bar blade grinder of this invention includes a grinding wheel Ii! operated by a motor I I and vmountedon a carriage I2 with the carriage adapted to travel on a frame I3, and with the frame'adapted to hold a sickle bar I4 having blades I5 thereon.

The wheel ID is formed with recesses I6 and Il in the ends and a'web I8 between the recesses is provided with a bore I9 by which the wheel is mounted on a shaft 28 with the web held between collars 2| and 22 by'a lock nut 23, as shown in Figure 5. The shaft 20 is rotatably mounted in the ends of arms 24'and 25 and the outer end of the shaft is provided with a pulley 26 by which the grinding wheel is rotated with a belt 2l from a pulley 28. The pulley y28 is xedly mounted on a stub shaft 29 on-which the inner ends of the arms 24 and 25 are -pivotally mounted and on the opposite end of the vstub 'shaft 29 is a pulley 3i) that is drivenfrom'a pulley 3l on a motor shaft 32 by 'a belt 33. The armsr 'Z4 and`25 are held in spaced relation by a cross bar 34, as shown in Figure-4, andthe vbar 34 ispositioned in a yoke 35 at the upperend of a strut^3 which holds the armsand grinding wheel upwardl and elevates the wheel at theendof the stroke.

The inner ends ofthe arms 24 and 25 and th shaft 29 are fsupported invertically `disposed bars 3l and, 38 which are pivotally mounted in upwardly extending ends 38 and. 4I) of a bracket 4I, and the bracket is mounted on the carriagei I2 by -bolts 42. The bars 3land 38 are held in spacedrelation by a 'crossbar 43 which has threaded ends 44' and I5V that extend through the bars 31 and 38, respectively,v and the threaded ends are held by nuts 46 and 4'I. A threaded end 48 of a connecting rod 49 is held in the cross bar i9 by a nut 50 and the opposite end of the rod 49 is adjustably mounted in a slot 5I of an eccentric having a cam surface 52 and the eccentric is mounted on a shaft 53 that extends from a gear reduction unit 54. The end oi the connecting rod 49 is mounted in the slot of the eccentric by a pin 55 having a head 59 on the inner end, as shown in Figure 4.

A nose 57 is provided on one end of the ec=1 centric having the cam surface 52 and an arm 59 is positioned to be engaged by the cam surta-ce wherein with the arm 59 pivotallymounted on a pin 59 in a bracket 60, a projection Si on the op posite end of the arm will move upward as indifcated by the arrow 52 as the cam engages the arm 58. An adjusting screw 93 is provided in the projection I and the screw is positioned to engage a link 94 pivotally mounted at one end on the pin 59, and pivotally connected, at the opposite end to the lower end of the strut 99, by a pin B5. By this means the eccentric 52, turning about the shaft 53 engages the arm 5S and raises the link 64 which moves the strut 39 upward, and the upward movement of the strut elevates the arms 2li and 275 and the grinding wheel i9, whereby with this movement properly timed the grinding wheel will be moved upward at the end o1" the stroke to clear the blades of the sickle bar.

As the grinding wheel moves upward at the end oi the stroke the eccentric 52 continues to move and in the return stroke the carriage I2 is moved forward one step wherein the grinding wheel is positioned between the next pair oi blades, and then the forward movement of the wheel is repeated. The forward movement of the carriage is accomplished by a dog 5t pivotally mounted on the lower end oi a crank 57 by a pin 98, as shown in Figure 6, and the crank is pivotally mounted on a pin 99 in a bearing 'i9 with the opposite end of the, crank connected to a link 'II by a pin 12. The link l! is carried by the end of a lever 'I3 which is pivotally mounted on a pin 74 that connects the lower end of the bar 38 with the end 49 of the bracket 4i, and the lever 'I9 is formed with a vertically disposed leg 'I5 at. the upper end of which is a projection in which is a set screw TI that is positioned to be engaged by the bar 38` as it is moved backward by the eccentric. With the parts arranged in this manner the bar 38 will strike the screw l? moving the leg I5 back and elevating the forward end of the lever I3 which will raise the end of the crank 5l and push the dog against the rack "i8, and as the rack is stationary on the frame I3 the carriage will move ahead.

The speed reduction gear unit 54 is mounted on the carriage by a post 89 and at one end of the unit is a pulley BI on a shaft 92 and the pulley is driven from a pulley 83 on a jack shaft 84 by a belt 85. The jack shaft 94 is also pro* vided with a pulley 85 by which it is driven from a pulley 9'1- on the motor shaft 92 by a belt 89. It will be understood that although V-belts are shown inV the drawings, belts of any other type may be used andl also that any other means may be used for driving the parts from the motor.

The frame I3 is formed with vertically disposed members 89 and 9.0. at the ends and members 9I between the ends, and the opposite ends of horizontal members 92 are supported by posts 93. Rails 94 and 95 are provided on the horizontal members 92 and rollers 96 are positioned 4 on the under side of the carriage I2 through which the carriage is mounted on the rails.

The upper ends of the vertically disposed members 39 and 90 carry an angle 9'I with a plate 99 on the upper surface thereof upon which a sickle bar I4 may be held by clamps 99 with the blades I5 resting on a ledge |00 at the outer edge of the plate. The clamps 99 are formed with handles IIlIv and downwardly'extending rods |92 the lower ends` of which are slidably held in an angle Ill3, and the clamps are held downward by springs I94 which bear against set collars i95, as shown.

The motor iI- is mounted on the upper surface of the carriage I2 and the jack shaft 94 is mounted in a bearing stand IOS on a bracket I9? extending upward iromrthe carriage.

With the parts `arranged in this manner a sickle or cutter bar with the blades or sections thereon is clamped on the upper plate 98 and with the grinding wheel Iii positioned at one end the motor is started and as the eccentric starts to turn the grinding wheel enters the space between a pair of blades grinding the sharp cutting edges thereof, and as the wheel reaches the end of the stroke it is raised, as hereinbefore described, and the carriage is moved ahead to position the wheel between the next pair of blades. This cycle of movements is continued until the last pair of blades are sharpened, although it will be necessary to sharpen the outer edges of the end blades by hand.

It will be understood that modiiications may be made in the design and arrangement oi the parts without departing from the Vspirit of the invention.

What is claimed is:

1. A sickle bar blade grinding machine comprising a frame, means mounting a sickle bar with blades thereon on the frame, a carriage mounted to travel on the frame in a direction parallel to the sickle bar, a V-shape grinding wheel carried b y the carriage, means reciprocating the grinding wheel toward and away from the sickle bar to grind the cutting edges oi a pair of blades, means elevating the grinding wheel at the end of each grinding stroke, and means moving the carriage to shift the grinding wheel from one pair of blades to another pair of blades.

2. In an automatic grinding machine for sickle bars and the like, a frame having a horizontally disposed work holding plate and a track thereon with the track positioned parallel to the plate, a carriage having wheels positioned to travel on the track, a grinding wheel pivotally mounted on the carriage, means'rotati-ng the grinding wheel, actuating means feed-ing the grinding wheel along cutting edges of blades of the sickle bar, and means synchronized with the feeding means of the grinding wheel for intermittently moving the carriage.

3. In an automatic grinding machine for sickle bars and the like,l a frame having a horizontally disposed work holding plate and a track thereon with the track positioned parallel to the plate, a carriage having wheels mounted on the track, a grinding wheel rotatably mounted in the ends of arms rockably mounted on the carriage, an eccentric for actuating the.. arms and wheel with a reciprocating motion, means elevating the grinding wheel at the end of the. stroke, means rotating the grinding Wheel, and means moving the carriage on the track.

4.. An automatic grinder for blades of sickle bars of mowers and the like comprising a frame having a work holding plate and a track thereon with the track parallel to the plate, means clamping a sickle bar on the work holding plate, a carriage mounted on wheels positioned to travel on the track, a rack on the frame, a dog, means pivotally mounting the dog on the carriage with the dog positioned to engage the ra-ck to move the carriage, a V-shaped grinding wheel, horizontally disposed arms in the ends of Which the grinding wheel is rotatably mounted, vertically disposed bars pivotally mounted on the carriage with the arms in which the grinding Wheel is mounted pivotally mounted in the upper ends thereof, an eccentric for actuating the vertically disposed bars and grinding wheel with a reciprocating movement, a cam on the ec-centric for raising the grinding wheel at the end of the grinding stroke, and a lever positioned to be actuated by the vertically disposed bars for operating the dog to move the carriage.

5. In an automatic grinder, the combination, which comprises, a frame having a work holding plate longitudinally positioned thereon, clamping means on the plate, a. track positioned parallel to the plate also mounted on the frame, a carriage having wheels mounted to travel on the track, vertically disposed bars pivotally mounted on the carriage. horizontally disposed arms carried by the upper ends of the bars, a V-shaped grinding Wheel, means rotatably mounting the grinding Wheel between the ends of the arms, driving means for the grinding wheel mounted on the carriage, an eccentric mounted on the carriage and connected to the vertically disposed bars for reciprocating the bars and grinding wheel, a cam on the eccentric, means elevating the grinding wheel by the cam at the end of the grinding stroke, and means moving the carriage a predetermined distance at the end of the grinding stroke.

PAUL RAINBOLT.

CLEO E. BARBER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS' Number Name Date 1,182,615 Armstrong May 9, 1916 FOREIGN PATENTS Number Country Date 220,332 Great Britain Aug. 11, 1924 

